In the past several years, legal suppressor production has exploded. In 2014 the NFRTR listed 571,150 registered silencers while information released earlier this year showed 792,282– a growth of some 39 percent. The numbers of NFA-compliant suppressors currently listed nearly eclipse the total number of select-fire weapons, short-barreled rifles, and short-barreled shotguns, combined.

http://www.guns.com/2015/10/22/bill-introduced-to-remove-suppressors-from-nfa-regulation/

David